The 1,2,4-triazole nucleus is an important pharmacophore found in antifungal, antitubercular, antiparasitic, antileukemic, and antitumor therapeutic agents. Certain 1,2,4-triazoles have a direct action on leukemia. Certain 1,2,4-triazoles also serve as therapeutic adjuvants by suppressing azole-resistant fungal infections associated with cancer chemotherapy. Several N-substituted 1,2,4-triazoles, including anastrozole, letrozole, and vorozole, act as aromatase inhibitors, and show impressive activity in the treatment of advanced breast cancer. These established antitumor triazoles are useful as templates for new generations of candidate chemotherapeutics for estrogen- and androgen-dependent diseases, based on 1,2,4-triazoles.
5-Nitrofuran derivatives were the first commercially known nitrogenous heterocycles of medicinal value, primarily because of their effectiveness against both Gram positive and Gram negative bacteria. However, their use in treating human infections has always been highly problematic. Over 4,000 nitrofuran-based therapeutic compounds have been synthesized and tested for their biological effectiveness to date, despite the fact that the nitro functional group has been reported to be carcinogenic, and to cause methemoglobinemia. Sustained oral administration (although not long-term topical application) has been associated with hepatic and pulmonary toxicities. Some of the more commonly known 5-nitrofuran-based therapeutics include nitrofurantoin and nitrofurazone (FIG. 1), both of which are widely utilized as antibacterial, agents.